Equipment for cleasing and/or sterilising the filler tube in packaging machines

ABSTRACT

APPARATUS FOR WASHING THE FILLER TUBE OF A LIQUID PACKAGING MACHINE WITH A WASHING AGENT INCLUDING MEANS FOR CLOSING ONE END OF THE PACKAGING TUBE TO FORM A SPACE THEREABOVE AND MEANS FOR INTRODUCING A WASHING AGENT INTO THE SPACE AND FOR HEATING THE AGENT SO AS TO CLEANSE AND/OR STERILIZE THE FILLER TUBE EXTENDING INTO THE PACKAGING TUBE.

' A. TUMA ETAL 3,716,083

Feb. 13, 1913 EQUIPMENT FOR, CLEANSING AND/OR STERILISING HIE FILLERTUBE IN PACKAGING MACHINES Original Filed Feb. 17. 1969 2 Sheets-Sheet 1Fig.1

III III] Feb. 13, 1913 TUMA ET AL 8.7165083 EQUIPMENT FOR, CLEANSINGAND/OR STERILISING THE FILLER TUBE IN PACKAGING MACHINES Original Filed.Feb. 17. 1969 2 Sheets-Sheet 2 Fig.2

U.S. Cl. 141-90 5 Claims ABSTRACT OF THE DISCLOSURE Apparatus forwashing the filler tube of a liquid packaging machine with a washingagent including means for closing one end of the packaging tube to forma space thereabove and means for introducing a washing agent into thespace and for heating the agent so as to cleanse and/or sterilize thefiller tube extending into the packaging tube.

This application is a divisional application of our earlier filed patentapplication Ser. No. 799,560, filed Feb. 17, 1969 now Pat. No.3,615,823.

This invention is related to packaging technology and is concerned wth amethod of, and equipment for, cleansing and/ or sterilising the fillertube in packaging machines of the kind which form a packaging tubearound the filler tube, and where the packaging tube, while partiallyfilled with the liquid to be contained in the packages, is divided intofilled and sealed packages at the same time as the column of liquid inthe packaging tube is also divided.

The demand for a sterile packaging process, particularly in connectionwith the packaging of goods such as milk which offer a conductiveenvironment for bacteria, has been increasing. These demands have beenfurther accentuated in connection with aseptic packaging of sterileliquids, and a number of methods have therefore been proposed forbringing about satisfactory aseptic conditions when such goods are beingpackaged. One method e.g. aims at sterilising the inside of the fillertube, and the method is used for filler tubes where there is apossibility of circulating the cleansing agent. With these filler tubes,circulation washing and sterilisation are carried out right down to abase plate attached to the opening of the filler tube during the washingoperation.

One aim of this invention is therefore to supplement such a sterilewashing process by cleansing and sterilising the outside of the fillertube as well. This aim has been achieved by this invention, which ischaracterised by the lower end of the packaging tube being closed by adevice, whereby the packaging tube and the device together define aspace which is supplied with a cleansing and/or sterilising agentthrough a duct in the device, at least up to that level which the liquidsurrounding the filler tube reaches while the packaging machine is inoperation, after which the cleansing and/or sterilising agent is heatedto a suitable cleansing and sterilising temperature.

In order to clarify still further the subject matter of the invention,it may be mentioned that in packaging machines of the above kind theliquid is introduced into the packaging tube below the liquid level, andthere is therefore great danger that some of the liquid will be leftbehind on the outside of the filler tube. This danger is particularlygreat when operation of the machine is stopped either temporarily or forthe day. In either case the outside of the filler tube, where one orperhaps several individual microorganisms may find good conditions forgrowth in the substrate, is a potential source of con- United StatesPatent G Patented Feb. 13, 1973 tamination unless measures are taken, onthe one hand, to prevent adhesion of the substrate to the outside of thefiller tube and on the other, to ensure that any organisms there may bepresent will not survive. It may be mentioned further that the packagingtube is made use of during cleansing and sterilisation of the outside ofthe filler tube to form the walls of a container for the reception ofthe cleansing, sterilising and rinsing agents.

There are a number of advantages in cleansing and/ or sterilising theouside of the filler tube by the method specified in the invention, ascompared with processes used earlier. The method is thus simpler andrequires less time than if washing were carried out manually, sincethere is no need to remove and to dismantle the apparatus. Asepticconditions are in addition maintained when the method in accordance withthe invention is used in the event of a breakdown in operation or whenwork is finished. A further advantage is that only the area actuallyexposed to danger is sterilised, which means, among other things, thatparts of the machine which do not have to be subjected to such harshtreatment will not become overheated or be exposed to chemical attack,and it is further possible to carry out this cleansing and/ orsterilisation processes of the milk steriliser or other components usedin conjunction with the sterile filling operation.

The invention is also concerned with equipment to be used for carryingout the method specified, the equipment being characterised by asupporting arrangement designed to be fitted around a packaging tube,and by a devise designed to be introduced into the packaging tube,whereby the device consists of a plate, disc or similar component,having (a) a sealing strip around its periphery, the sealing strip beingdesigned to form a liquid-tight seal against the inside of the packagingtube,

(b) a combined supply and drainage duct for the cleansing and/ orsterilising agent,

(c) piping connected to the combined supply and drainage duct for thesupply of the cleansing and/ or sterilising agent into the space definedby the inner side walls of the device and of the packaging tube, and toremove it therefrom,

(d) surfaces on the inner side Wall which slope towards the combinedsupply and drainage duct, and

(e) a heating coil designed to heat the cleansing and/or sterilisingagent.

Further advantages and objects of the invention will be apparent fromthe following description of the invention, reference being made to theattached diagrammatic drawings of which FIG. 1 shows, in partial crosssection, equipment for carrying out the method in accordance with theinvention, and

FIG. 2 shows, also partially'in cross section, a part of the equipmentdepicted in FIG. 1, to an enlarged scale.

Reference 1 in FIG. 1 denotes a packaging tube which consists of paper,aluminum or a plastic material, or of a combination of these materials,and which has been formed around a filler tube 2 designed to introduceliquid into the tube 1. Reference 3 denotes a plate which has a sealingarrangement 4 around its periphery. There is furthermore a combinedfilling and drainage hole in the plate 3 for the cleansing and/0rsterilising agent which is supplied through the piping 9. The plate 3also has a heating coil 10 with inlet and outlet pipes 11 and 12respectively. The plate 3 and its sealing arrangement 4 are designed toform a liquid-tight seal in the packaging tube 1, whereby the plate 3and the packaging tube 1 will form a container 13 for the cleansingand/or sterilisation process.

The plate and its attachments, as well as their working will now bedescribed more closely by reference to FIG. 2. The plate 3, as has beenmentioned before, has a sealing arrangement 4 which is designed to forma liquid-tight seal in the packaging tube 1. The sealing arrangementconsists of a sealing strip 5 and a supporting unit or pressure ring 6which surrounds and is in contact with the tube 1 opposite thecircumference of said strip. The sealing strip 5 consists at leastpartly of material that can be deformed, such as rubber, and may in itssimplest version consist of a hose, a pipe vulcanised into a hose, orsimilar. As may be seen on the figure, the sealing strip 5 is seated ina groove at the peripheral edge of the plate 3. The sealing strip 5 isfurthermore connected to a tube 7 which is intended to convey to theinside of the sealing strip a pressurised agent, e.g. a gas underpressure such as compressed air. One of the functions of the presurering 6, which is fitted around the free portion of the sealing strip 5,is to shape the sealing ring and to prevent its deformation in theradial direction. The plate 3 is intended to be introduced into thepackaging tube in such a way that the sealing strip 5 will be inside thetube and the pressure ring 6 outside the tube at the same level as thestrip. When the setling strip 5 is subjected to pressure by theintroduction of a pressurised agent through the pressure hose 7, thesealing strip will exert pressure against the inside of the packagingtube, which pressure and the area under pressure, or in other words thesealing surface, will be caused to increase owing to the action againstthe pressure ring 6. The sealing procedure may be described in otherwords by saying that the wall of the packaging tube 1 is clamped betweenthe sealing strip 5 and the pressure ring 6, such clamping being theresult of pressure from inside the tube (towards its inside surface and)radially outwards. The upper side of the plate 3 which faces the lowerend of filler tube 2 should preferably have a somewhat conical orconcave shape sloping downwardly towards the combined filling anddrainage hole 8 for the cleansing and/or sterilising agent in the plate3. The piping 9 is connected to the hole 8 which should preferably besituated at the centre of the plate 3, and functions to supply thecleansing and/or sterilising agent to the space 13 above and defined bythe plate 3 and the packaging tube, and to remove it therefrom. Theplate 3 also supports the heating coil 10, in the shape of e.g. a helix,which is intended for heating the cleansing and/or sterilising agentintroduced into the space 13. The heating coil 10 is located adjacentthe conical side of the plate 3 and is arranged so as to surround thelower end of the filler tube 2. The heating coil 10 is also connected toinlet and outlet pipes 11 and 12 respectively which pass through theplate 3. The inlet and outlet pipes 11 and 12 respectively are fittedwith surrounding handles 14 and 15 and the outlet pipe 12 may inaddition be fitted with a. steam trap 16 when the heating medium issuperheated steam. The heating coil 10 may naturally be designed to beheated in another way, e.g. electrically.

The method of operation of the above equipment will now be described,the expression cleansing and/ or sterilising agent used heretofore beingreplaced by the term washing agent which is intended hereinafter and inthe appended claims to refer to a cleansing agent, a sterilizing agentor a combination thereof.

When the outside of the filler tube 2 is to be cleansed and/orsterilised, the plate 3 is fitted into the free end of the packagingtube 1 which has been obtained by tearing off or in some similar way,care being taken at the same time that the tube material is insertedbetween the sealing strip 5 of the plate 3 and the pressure ring 6. Theplate 3 is furthermore inserted into the tube 1 in such a way that theheating coil 10 is situated around the lower, outlet end of the fillertube 2. In order to retain the plate 3 in the tube 1, a pressurisedagent such as compressed air is admitted through the pressure hose 7,whereby the sealing strip 5 is pressed against the inside of thepackaging tube 1 and against the pressure ring 6 situated outside thetube 1. This operation at the same time produces a liquid-tight sealbetween the plate 3 and he packaging tube 1, the seal being accomplishedfrom the inside of the tube 1 radially outwards, A well-defined space 13is thus obtained for the cleansing, sterilising and rinsing agents, thespace 13 being bounded by the plate 3 and the packaging tube 1. Washingagent is then introduced into the circumscribed space 13 through thewashing agent pipe 9. The washing agent is admitted into the space 13 upto a level 18 such that the washing agent surrounds the filler tube 2 toa level higher than that of the liquid contained in the packages whenthe machine is in operation. The washing agent is then heated to boilingtemperature with the aid of the heating coil 10, during which operationthe washing agent is caused to circulate in the space 13 so that evensuch parts that are difficult to cleanse will be efficiently cleansed.After some time, when the cleansed or sterilised parts have been freedfrom particles of impurity and the like, the space 13 is cleared ofwashing agent through the piping 9 afiixed to the plate 3. The space 13may in the end be rinsed if desired by e.g. sterile hot water alsointroduced and drained away through the washing agent pipe 9. A fillerpipe with a sterile outer surface will thus be obtained by the method ofoperation described above.

When the machine ceases to portion out liquid, e.g. overnight, the plate3 and its ancillary equipment are fitted into the packaging tube 1 andare made to form a seal against the tube wall, after which at least onecleansing of the apparatus is carried out with a view to removing liquidthat has been left behind. Before the machine is started up again, e.g.the next morning, another cleansing operation may be carried out ifdesired, but the apparatus must be sterilised at least once this time,as described above. When this has been done, the pressure in the sealingstrip 5 of the plate 3 is released, so that the plate may be removedfrom the packaging tube 1 and put to the side, after which the machinemay be started up. The apparatus is to be used in the way described evenwhen the machine is out of action for a short time. A cleansing andsterilising operation using the above method and equipment may becarried out at any time when the machine is out of action.

In a test series using the equipment and the method specified in theinvention, milk suspension containing spores of Bacillus subtilis as thecontaminating agent, and a 2% caustic soda (NaOH) solution as theWashing agent, were used.

During the tests, the 2%caustic soda solution was heated by the heatingcoil 16 which consisted of copper tubing. Steam, having a temperature of145 C, (293 F.) and maintained at a pressure of 4 at. g. (59 p.s.i.g.)was continuously supplied to the heating coil 10 through the inlet pipe11. The steam was exhausted through the outlet pipe 12 and hadatmospheric pressure and a temperature of approximately C. (212 F.)beyond the steam trap 16. After the washing operation, which went on for10 minutes, the filler tube 2 was rinsed using sterile distilled waterat room temperature, in order to neutralise any caustic soda solutionleft behind. The filler tube was then swabbed with beef tea that hadbeen incubated for seven days at a temperature of 30 C. (86 F.), andcll'lecks were then made to find out if growth had taken p ace.

It was found that the equipment and the method specified in theinvention lend themselves well to removal of all substrate particlesremaining on the outside of the filler tube, and to sterilisation of theoutside of the filler tube, without this having to be dismantled formanual cleansing and decontamination. It was further established, bycarrying out a number of test series, and varying the washing period,that sterility was attained with a suflicient margin of safety when awashing period of 10 minutes was used.

It is naturally possible, within the framework of the idea underlyingthe invention, to modify both the equipment described and the method ofcleansing and sterilising the outside of the filler tube. The pressurering may thus be attached to the plate, by making it in the shape of a Uso that its legs reach round the lower free end of the packaging tube.The sealing strip may also con sist of several parts, one of these partsbeing that capable of deformation which will constitute the means ofaccomplishing the seal. There is no need for the plate to be solid; itmay for instance consist of two discs situated at a certain distancefrom one another, the sealing strip being clamped between these discs.The inlet and outlet pipes for the heating coil may be situated next toone another so that they can be fitted with a common handle.

We claim:

1. Apparatus for washing the filler tube in liquid packaging machines inwhich a packaging tube surrounds the filler tube and extends below thefiller tube comprising sealing means adapted to be inserted into thepackaging tube below said filler tube to form a seal with the packagingtube and thus form an enclosed space therea'bove, conduit means forintroducing and withdrawing a washing agent through said sealing meansinto and from the space thereabove, the washing agent being introducedto a level at least as high as the level of the liquid surrounding thefiller tube when the packaging machine is in normal operation, saidsealing means having an upper conical surface, the lowest point of whichsubstantially coincides with the conduit means for introducing andwithdrawing the Washing agent and means mounted on said sealing meansand disposed Within the space there- 6 above for heating said washingagent, said heating means surrounding the filler tube within thepackaging tube.

2. Apparatus as claimed in claim 1 wherein said sealing means includes adisc and an inflatable annulus around the periphery thereof and meansfor inflating said annulus to seal said disc within the packaging tube.

3. Apparatus as claimed in claim 2 and further comprising a pressurering disposed about the outside of the packaging tube at that level atwhich the sealing means is located for receiving pressure from saidannulus when inflated to prevent deformation of the packaging tube.

4. Apparatus as claimed in claim 1 wherein said heating means comprisesa helical tube for conducting steam therethrough.

5. Apparatus as claimed in claim 1 wherein said heating means comprisesan electrical heating element.

References Cited UNITED STATES PATENTS 3,274,700 9/1966 Maguire, Sr. etal. -l34105 X 576,945 2/1897 Brenneman 134--l66 C UX 1,215,189 2/1917Price 134-l66 C UX 3,359,062 12/1967 Palm 141-90 X FOREIGN PATENTS1894A.D.7030 2/ 1895 Great Britain 13893 HOUSTON S. BELL, JR., PrimaryExaminer UJS- Cl. X.R.

2l93; 53167; 134- 105, 166 C; l4191

